The ultimate objective of this program is to determine if there may be detrimental health effects associated with human use of marihuana or other drugs because of their retention in the body as fatty acid conjugates. We have previously identified long-retained cannabinoic metabolites, isolated from rats given I.V. or I.P. injections of 14C-delta8-THC or 14C-delta9-THC, as primarily conjugates of palmitic and stearic acid, with lesser amounts of C18-unsaturated fatty acid conjugates. We propose in this research program to determine distribution and pharmacokinetic data on the cannabionic conjugates in rats, and also to determine if they are psychoactive. Studies will also be performed to determine if the conjugates have adverse or toxic effects as have been seen with other cannabinoids. Other drugs, such as codeine and morphine, will also be analyzed to determine if they may also be conjugated to fatty acids.